1. Field of the Invention
The present invention relates to hinge systems, and in particular, to a quick release hinge system that exerts minimal friction force during the insertion and removal of the pin.
2. Description of the Prior Art
Traditional hinge systems consist of a series of pad eyes that are alternately attached to two separate structures that are intended to be hingedly connected. Each of these pad eyes has a hole having the same diameter, with the centers of the holes aligned in a straight line. A cylindrical pin is then inserted into the aligned holes to join the two structures together. These two structures can then be pivoted about an axis defined by the pin. A very simple example of such a hinge system can be found in doors.
Floating structures can also be connected using the conventional hinge system described above. When two floating structures are being connected in a controlled environment, the state of the sea is generally calmer so that the centers of the holes in the pad eyes can be visibly aligned to receive the pin. Therefore, the connection operation is easy and safe to perform.
However, after the structures have been connected for a period of time, the weight or flotation distributions of both structures could be altered due to other operational requirements. In effect, the extra weight from one end of one structure may be supported by the flotation of the other structure. As a result, large amounts of shear force can be accumulated in the pin. The shear force creates friction force between the pin and the pad eyes, which makes it difficult to pull out the pin when the two structures need to be separated. Without monitoring the magnitude of the shear force, the operator will have difficulty estimating the equipment needed to pull out the pin if the two structures are to be separated. If the shear force is high, the two structures will move rapidly opposite to each other once the pin exits the last pad eye because there is no shear force to hold the two structures together. In general, the harder the pull, the higher the shear force exists, and the faster the resulting relative motions of the two structures. If the sea environment happens to be rough at the time of the separation operation, this operation will be much more dangerous and difficult when compared to the initial connection operation, thereby increasing the possibility of structural damage to the structures, and human injury.